For the first time in 20 years, the number of households in the U.S. that have TV sets has declined. Neilsen cites the decline as a symptom of poverty and young people’s consumption of content online.

The latest data from the company, which takes TV set ownership into account when it calculates ratings, shows that 96.7% of U.S. homes own a TV set. This figure is down from 98.9% from its last count. There are now 114.7 million TV homes, down from 115.9 million.

Neilsen suggests that possible reasons for the decline are that some low income houses, particularly in rural markets, can no longer afford TV sets, and that some younger Americans don’t even buy TVs when they graduate from college or start working – at least not right away. The transition to digital TV in 2009 was also listed as a potential factor, as digital cable is expensive.

“While Nielsen data demonstrates that consumers are viewing more video content across all platforms – rather than replacing one medium with another – a small subset of younger, urban consumers seem to be going without paid TV subscriptions for the time being,” the company said.

Overall, the company is, at least for now, blaming the economy for the decline in TV sets. The previous decline in the number of TV sets was in 1992 – and it was also temporary and a result of a prolonged recession.